Spinal interbody fusion is frequently performed procedure to treat various disorders such as degenerated disk disease, spondylolisthesis, trauma, infection, tumor and deformity. Usually, surgery involves placement of screws into the vertebral body through the vertebral pedicle and/or placement of an interbody cage with bone grafts into the disc space. Types of spinal fusion depend on the approach type such as posterior, transforaminal, lateral, etc. Although these approaches claim to be minimally invasive, they still require open incisions for cage and screw placement. For example to perform one level interbody fusion the surgeon must perform an incision to perform discectomy and insert a cage, then four incisions to insert pedicle screws and then two more incisions to pass rods and stabilize screws to rods.
During spine stabilization operations a certain degree of compression or distraction is usually applied to stabilized vertebrae depending on the condition. Compression is usually performed on the concave side of the scoliotic deformity to correct it.
Distraction on the other hand is opposite to compression and is performed usually to decompress vulnerable structures that travel between vertebrae, i.e. nerve roots. Distraction is usually performed so as to increase the gap between vertebral bodies to decompress nerve roots escaping from neural foramina. It is also is performed on the convex side of scoliotic deformity.
Improvements in fusion, compression and distraction methods and devices are therefore desired.